Instrument for severing tissue with HF current

Details Instrument for severing tissue with HF current Instrument for severing tissue with HF current

1999-12-04

2001-12-04

Peffley, Michael (Department: 3739)

Surgery

Instruments

Electrical application

C606S041000, C606S045000

Reexamination Certificate

active

06325801

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to an instrument of cutting tissue.
PRIOR ART
An instrument for cutting tissue is known from the U.S. Pat. No. 5,423,830. That instrument, which is intended, express is verbis, for removal of adenoids, includes an HF coil which is pushed over the adenoid. Then the adenoid is aspirated into a suction cup and the base of the adenoid is then severed with the coil.
The known instrument is hence not appropriate for severing tissue, specifically mucous membrane material, in the form of strips, as it is necessary, for instance, in certain treatment operations on elongate organs, e.g. the oesophagus.
An instrument of a slightly varied type is known from the German Patent DE 44 29 478 C1. That instrument includes, in addition to a cutting means operated with high frequency, an extractor tube through which the severed tissue fragments may be aspirated. This instrument, too, is not suitable for severing tissue such as mucous membrane material in strips.
BRIEF DESCRIPTION OF THE INVENTION
The present invention is based on the problem of providing an instrument for severing tissue with HF current, which is suitable for severing the tissue in the form of strips having a specified thickness.
In accordance with the invention the body of the instrument comprises an aspirator element in the region coming into contact with the tissue, to which element a negative pressure is applied by means of the suction means such as a pump in a way that tissue is aspirated to the instrument body, particularly in the region of the aspirator element. In distinction from prior art, it is intended here that the tissue is not aspirated into the instrument body but should merely “adhere” to the instrument body under the suction effect. For severing strip-shaped tissue fragments having a substantially constant thickness at least one part of the electrode system is moved in parallel with the aspirator element in such a way that the tissue aspirated to the instrument body is removed between the aspirator element and the moving part of the electrode system.
Even though the aspirator element may also be provided in the distal face of the instrument, an improvement is preferred whereby the aspirator element has a preferably cylindrical outside surface in which a hole array with at least one hole is provided or which is of a permeable design. The negative pressure is then applied to the cylindrical outside surface from inside. If a hole array is used it is preferable that this array includes a plurality of holes of a comparatively small diameter because in such a case a high aspiration effect is achieved without the potential risk of tissue being “sucked into” the instrument body.
The HF electrode system in the instrument may be both a monopolar electrode, with the backplate electrode being mounted on the body at a distance, and a bipolar electrode array.
When the instrument comprises a monopolar electrode the latter is formed by the mobile part of the electrode array whilst the other electrode is (preferably) constituted by the cylindrical outside surface.
Independently of the use of a monopolar or bipolar electrode array it is preferable that the mobile part of the electrode array presents the shape of an HF cutting coil known per se. The precise form of the coil or loop is adapted to the outside contour of the aspirator element.
The coil is disposed at a predetermined spacing along a direction normal on the surface of the aspirator element, which space determines the thickness of the severed tissue strip. For tissue cutting the coil is preferably moved from the distal end towards the proximal end because the power transmission is easier to “dose” when working in “traction mode” than this would be the case when working in “pressing mode.”
A particular embodiment of the inventive instrument in which substantially unvaried or only slightly modified “modular elements” of known endoscope and HF resection systems may be used: in this design the instrument body comprises a first hollow shaft which corresponds essentially to known endoscope shafts. This hollow shaft is so modified that it carries the aspirator element laterally. On its proximal end a connector known per se is provided for the suction means, such as a suction pump which may be a glass filter pump, a reciprocating pump, a rotary pump or the like.
A particularly low-cost production and moreover the suitability for easy sterilization and cleaning of the inventive instrument are achieved by the provision that the lateral hole array or the permeable region, is provided in the external wall of a hollow body which is inserted into a recess in the first shaft. The hollow body may consist of an electrically insulating material, e.g. a ceramic or glass material, quartz or a synthetic material, especially when the electrode array is a monopolar electrode.
In such a case it is preferable that the hollow body is transparent because in such a case an observation is possible by means of an endoscope inserted into the first shaft through the transparent hollow body. When comparatively wide holes are used it is possible, of course, to produce the hollow body also from a non-transparent material and to provide for observation through the holes.
Instead of an optical lateral viewing endoscopic system also an optical retro-system may be used which projects beyond the distal end of the first shaft. In the event that the optical endoscopic system is guided through the duct of the first shaft, through which the material is also withdrawn, a seal must possibly be provided on the distal end.
In any case, it is preferable that the optical endoscopic system is suitable for axial displacement.
In further embodiments, the hollow body is inserted into a supporting element together with which it is inserted into the first shaft, and the supporting element is fastened in the first shaft by means of a screw introduced into the distal face of the first shaft, to improve the suitability of the instrument for cleaning and sterilizing.
To permit a simple displacement of the mobile electrode with a small structure and, particularly, a low lumen requirement, a feeder line for the current supply of the electrode array is arranged outside the axis in the first shaft and configured as a connecting or traction rod; furthermore, a handle is attached on the proximal end of the traction rod, and a manipulator is disposed on the first shaft.


REFERENCES:
patent: 3835842 (1974-09-01), Iglesias
patent: 5275609 (1994-01-01), Pingleton et al.
patent: 5423813 (1995-06-01), Kaiser et al.
patent: 5423830 (1995-06-01), Schneebaum et al.
patent: 5527332 (1996-06-01), Clement
patent: 5913857 (1999-06-01), Ritchart et al.
patent: 6019733 (2000-02-01), Farascioni
patent: 6030383 (2000-02-01), Benderev
patent: 6077230 (2000-06-01), Gregoire et al.
patent: 6142955 (2000-11-01), Farascioni et al.
patent: 6197025 (2001-03-01), Grossi et al.
patent: 44 29 478 C1 (1996-03-01), None
patent: 195 01 258 A1 (1996-07-01), None

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